> I'm sure Dwight Read will answer on his own, but let me jump in. The
And me too...

> chimp average brain size is about 400 cc, perhaps a little less, and the> gracile australos about 450. The robusts, except for WT 17000 (wich is> around 410 cc) are all around 520-53O cc.> But I still think that tool-making is but one aspect of social> behavior. The tripling in brain size requires at least two components to> be integrated: body size, i.e., allometric relationships, and secondly> brain expansion without concomitant body size increase. Very difficult to> know exactly how much is the former and the latter.

And then on top of that is the *worst* problem of all.... there seems to
be no real correlation between the archaeological record and the increase
in brain size. This I find MOST frustrating, annoying, and provocative.
Are there any GOOD differences in the toolkit of late erectus and early
sapiens? What about 'archaic' and modern sap? And worstest of all,
perhaps, any good physical differences between early moderns and the
moderns who appear to have done nifty things like art, agriculture and the
like....